Authorities say Irina Walker and her husband, a former sheriff's deputy, staged at least 10 cockfighting derbies between April 2012 and April 2013 at their ranch in Irrigon — 175 miles east of Portland. Blades were attached to the birds' legs, spectators were charged admission, and food and drink were sold, the indictment said. The fights allegedly brought in as much as $2,000 a day.

The Walkers were charged with unlawful animal fighting, conspiracy to violate the animal welfare act and operating an illegal gambling business. Both have change of plea hearings scheduled for July 16 in Portland. Their trial had been scheduled for July 14.

Federal prosecutor Stephen Peifer confirmed that Irina Walker is scheduled to plead guilty, but declined comment when asked the terms of any plea agreement. Walker's lawyer, Per Ramfjord, was out of the office Thursday and didn't return a message.

Irina Walker is the third daughter of former Romanian King Michael I. Michael, now 92, was forced to abdicate by the communists in 1947.

Walker's daughter, Angelica Kreuger, told the AP last year that her mother moved to the U.S. from Switzerland in the early 1980s with her former husband.

Kreuger said her mother never lived a lavish lifestyle. She rode horses, gardened, studied the Bible and raised two children while living in southwest Oregon. She later divorced her husband and married a man who had been a family friend and neighbor — former Coos County sheriff's deputy John Walker. The couple moved to eastern Oregon.

More than a dozen other people were charged in connection with the cockfighting business. Some pleaded guilty in a companion case from Washington state and had their District of Oregon charges dismissed, court records show.

One co-defendant, Apolinar Munoz Gutierrez, also known as Polo, pleaded guilty in Portland Thursday afternoon to animal fighting and being an illegal alien in possession of a firearm.

The 38-year-old from Mexico acknowledged he was in the country illegally and that authorities found two pistols when they searched his residence on Wagon Wheel Loop in Irrigon.

Polo also admitted bringing his roosters to fight at the Walker ranch. He faces a maximum of 15 years in prison at his Sept. 25 sentencing.